Open heart surgery for a left atrial mass extraction during cardio-pulmonary bypass (CPB) in a 9 yoa Labrador dog

ranko

Dr Ranko Georgiev

Ranko Georgiev1, Stoyan Nikolov2, Nadezhda Petrova3

Georgi Ignatov4, MD Thoracic Surgery

1,2,3 DVM, Central Veterinary Clinic, Sofia, Bulgaria

4 MD, City Clinic Cardiovascular Center, Sofia, Bulgaria

1rankoge@gmail.com

 

Introduction:

 

Open heart surgery during a cardiopulmonary bypass is the only effective approach for some diseases that require an access to the heart chambers or the great vessels; even when a temporary inflow occlusion is chosen as an alternative, only a very few “time restricted” procedures could be done on a beating heart. However, when considering an open heart surgery, the high risk of intra- and post- procedure complications often outweighs the benefits. In veterinary medicine the financial weight of such a procedure is also a limiting factor.

We would like to share a case where a temporary sinus arrest was induced during a cardiopulmonary bypass and a huge mass was successfully extracted from the left atrium of a dog with an open heart approach.

 

Case presentation:

 

Artur 1

This is the patient just before the surgery

Arthur is a 9 year old MC Labrador, trained like a guide dog for a blind person, admitted because of increasingly frequent exercise intolerance episodes during the past few months. Furthermore, the last week the patient was very weak and experienced several syncopal episodes. On a clinical presentation with the referring vet а tachycardia and dyspnea were noted and the patient was referred to us for a Cardiology consult.

On physical examination, the dog weighted 25 kg, with a history of a rapid body mass loss for the last couple of months. His “normal” weight has always been around 32 kg according to the owners. The body condition was poor (score 2/5) and the dog had a grade II/VI left sided apical soft diastolic heart murmur. Lung auscultation was unremarkable, but the respiratory rate (RR) was more than 50 breaths per minute.Artur VD

Artur LLR

 

 

 

 

 

 

 

 

 

 

The X-rays of the chest were highly suggestive for e left sided congestive heart failure and showed mild generalized cardiomegaly with a VHS of 11.5 with enlarged left atrium and left ventricle. The pulmonary veins were slightly larger than the pulmonary arteries; the lung parenchyma with diffuse interstitial pattern in the area of the hilus. The patient was already on Furosemide in a low dose – 2mg/kg twice a day for the last two weeks with no improvement of the clinical signs.

 

 

A transthoracic echocardiography was done with the patient in lateral recumbence through the right and left parasternal windows. A huge echogenic mass with irregular shape was observed in the area of the left atrium – attached to the intra atrial septum and prolapsing through the mitral valve during diastole towards the left ventricle. The mass was creating almost full diastolic obstruction of the valve, allowing only a tiny fraction of the blood in.Artur_Ochi_na_4_lapi_20161116113435_1139400 Artur_Ochi_na_4_lapi_20161116113435_1140250 Artur_Ochi_na_4_lapi_20161116113435_1147090 Artur_Ochi_na_4_lapi_20161116113435_1837270 Artur_Ochi_na_4_lapi_20161116113435_1837510

Complete blood count, electrolytes and biochemical profile were normal. During the abdominal US study no further abnormalities were noted and no more masses found. On the ambulatory ECG a normal sinus rhythm was recorded with multiple atrial premature complexes. The blood pressure was normal. A hemo-culture and a urine culture were obtained and came back negative for a bacterial growth. The bleeding time and the Pt/APtT were normal.

A diagnosis of an intra atrial mass with clinical signs of a progressing left sided congestive heart failure was made and a surgery was discussed. Because of the location of the mass no surgical or interventional approach was possible without the aid of a cardiopulmonary bypass (CPB) and cardioplegia. All the risks and possible complications were discussed with the owner and a decision for such a surgery was made. The team for the surgery was from a veterinary surgeon, human cardiovascular surgeon, cardiovascular perfusionist, veterinary and human anesthetists, and nurses. The procedure was done in Central Vet Clinic, Sofia on 3rd of December 2016.

 

 

 

Artur 3

The heart-lung machine with 4 pumps – one main pump for the oxygenator and the blood, two for collecting the surgical field blood and one for the cardioplegique solution; the model is Sorin 5 with a pediatric small volume oxygenator

Our anesthesia protocol with this patient started routinely for the procedure of a thoracic surgery – premedication with Midazolam and Buprenorphine, induction with Etomidate, intubation and maintenance with Isoflurane. Additionally we put a bladder catheter for urine production measurement, central venous catheter, an intra-arterial catheter for a direct blood pressure measurement and tree peripheral intra-venous catheters. Many more drugs were used during the anesthesia and the long post-operative recovery period like Nitroglycerin, Atracurium, Protamine, Amantadine, Pyracetam, Efedrin, Dopamine, Methylprednisolone, Fraxiparin, Clopidogrel, antibiotics, etc.)

Artur 2

The busy surgical field – left lateral thoracotomy through the 5th intercostal space; visible are the venous, the arterial and the cardioplegique cannulae

Artur 7

the surgical ward during the procedure – a total of 10 people were simultaneously engaged in the procedure

Artur 5

the surgical ward during the procedure – a total of 10 people were simultaneously engaged in the procedure

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Artur 6

he extracted mass from the left atrium – Neurofibrosarcoma with size 8/6/4 cm

The surgical approach was through the left fifth intercostal space with a standard lateral thoracotomy. Additionally the left carotid artery was approached and prepared in case it is needed for the CPB blood return. The pericardium was excised and the left atrium, the big vessels and the left ventricle visualized. Then three cannulas were put – the one collecting the venous blood inside the right atrium (through the right atrium auricle), the one returning the oxygenated blood from the CPB machine into the ascending aorta and one small cardioplegique cannula into the aortic root over the coronary arteries. Then a bolus of Heparin was injected iv in a dose of 800UI/kg and 5 minutes later the patient was switched to the heart-lung machine (Sorin 5 and a pediatric oxygenator with 360 ml prime). Then we started a controlled cooling of the patient using a chiller, connected to the CPB machine. When the target body temperature of 28o C was reached the ascending aorta was cross clamped and a 600 ml of cooled to 4o C crystalloid cardioplegique infusion rich in potassium was infused through the coronary cannula producing complete heart arrest. We stopped the active ventilation of the lungs and the patient became fully dependent of the heart-lung machine. The heart was open through a 5 cm cut into the left atrial wall starting from the auricle tip. The mass was directly visualized and excised. It was connected to the intra atrial septum with a relatively small neck. We removed it without creating an ASD. The air from the heart was evacuated and the surgical cut closed with a 5-0 Polypropylene suture in a continuous way. The mass was a solid and well defined structure with irregular shape and was admitted for histology. The size was 8/6/4 cm.

We started a slow rewarming of the patient with a target body temperature of 38o C. Two epicardial electrodes were embedded and connected with an external pacemaker. Once closed and warmed, the heart was gently massaged manually for a couple of minutes and then hit with a direct pediatric defibrillator. We used 5 to 20J of energy shocks and got a slow and then faster rhythm after the 9th try. The external pacemaker was switched on and put on a 100 bpm rate for the next 12 hours. The surgical closure was uncomplicated and no significant bleeding was noted. The patient received slowly iv Protamin (1mg/100IU Heparin) as a Heparin antidote and the heart-lung machine was gradually restricted and then switched off. Two chest drains were put and connected to a sterile active suction. The total machine time was 130 min, the sinus arrest time – 22 min, total surgery time – close to 5 hours. Immediately after the CPB machine was stopped a hemotransfusion with two units of fresh blood was done.

Artur 10

the first 12 hours post the procedure Artur was kept on a Propofol CRI and with an external pacemaker set at a minimum of 100 bpm rate

Artur 9

the first 12 hours post the procedure Artur was kept on a Propofol CRI and with an external pacemaker set at a minimum of 100 bpm rate

Comments:

 

Arthur recovered from the general anesthesia slowly over the next 12 hours, but he was unable to stand on his feet for additional 5 days. The electrolyte levels, liver and kidney values were monitored almost every hour for the first 2 days and then three to five times a day; our main concern was the potassium blood level and we tried to maintain it stable at all times. The urine production was also constantly monitored and tailored to be in the normal range – with diuretics and blood pressure control drugs. From all the possible complications after a CPB we saw only a transient neurological signs attributed to some degree of brain injury – interpreted after the neurological exam as left sided forebrain lesion – ischemic or hemorrhagic. Arthur recovered completely both physically and mentally for the next two weeks with a lot of supportive care and physiotherapy. On discharge from the clinic he was able again to do all the things a blind person guide dog is trained to do. The histology report was made in a referral laboratory in Germany – Laboklin, and after the immunohistochemistry stain came back as a Neurofibrosarcoma.ran 2 ran 3

 

 

 

 

 

 

Artur 11

Artur reacted very well when in children company and we use this to stimulate his mental state (the authors’ youngest daughter)

Conclusions:

 

Artur 12

two weeks after the surgery with the owner

CPB is a routine everyday procedure in the human hospitals, usually carrying a good to excellent prognosis and very low mortality rate. On the other hand in the veterinary medicine field is still an exotic and very risky one. Although very demanding both for the clinical team and the patient himself, the cardiopulmonary bypass is the only option for cardiac diseases requiring an open heart surgery. We believe that a close relationship between a human medicine cardio surgical team and a small animal hospital team could make this type of procedures safer and better recognized.

We have done regular monthly rechecks on the patient with echocardiography and X-rays since then and now six months later Arthur is doing great, no drugs or any supportive therapy needed. He gained back his usual weight and is working like a guide dog every day.

 

Resection of a chest wall mass- surgical technique and peri-operative analgesia

12959354_10153530931267960_1853416198_o-200x300

Dr Vladislav Zlatinov

Corresponding authors :

Dr. Vladislav Zlatinov, Dr. Aglika Yordanova (Clinical pathologist), Dr. Nadejda Petrova (Anaesthetist)

 

Central Veterinary Clinic

Chavdar Mutafov str, 25 B, Sofia, Bulgaria

 

Introduction

 

Rib tumors are uncommon in small animals. Osteosarcoma (OSA) is the most common (73%). Other types include chondrosarcoma (CSA), fibrosarcoma (FSA), hemangiosarcoma (HSA).

Rib tumors tend to occur in large breed dogs and the usual location is in the costo-chondral junction. Radiographic changes include lysis, sclerosis, or a mixture of lytic and blastic patterns. Intra-thoracic invasion of adjacent pericardium and lung lobes is relatively common, so CT scans are recommended to determine the location and extent of the tumor, planning of the surgical resection, and clinical staging for pulmonary metastasis1.

 

Chest wall resection is recommended treatment for the rib tumors 2. The surgical approach is the identical to intercostal thoracotomy, but caudal and cranial margins include a minimum of one intercostal space and rib, while ventral and dorsal margins should be a minimum of 2 cm from the tumor.  Because of the large defect present, a need for autogenous and/or prosthetic reconstruction techniques is often necessary. Autogenous reconstruction techniques include the latissimus dorsi and external abdominal oblique muscles, and diaphragmatic advancement following resection of caudal rib tumors 3. Prosthetic reconstruction with non-absorbable polypropylene mesh, alone or in combination with autogenous techniques, is recommended for large defects. Autogenous reconstruction is preferred in humans because of a high complication rate associated with prosthetic mesh, such as infection and herniation. These complications are rarely reported in dogs following chest wall reconstruction with prosthetic mesh. Up to six ribs can be resected without affecting respiratory function in dogs 4.

Thoracic surgery in small animals is considered a painful procedure, resulting in alterations in pulmonary function and respiratory mechanics. Appropriate analgesic protocol may improve outcomes. Systemic administration of opioids and NSAIDs, intercostal and intrapleural blocks, and epidural analgesia are among the most common options for pain management after thoracic surgery in small animals 5.

 

 

Case report

 

A 10 years old male pitbull dog, weighting 24 kg was presented to us. The owners had been to three veterinary consultations before, the chief complaint being lameness at the right front limb. The cause was suggested to be a “lump” on the right thoracic wall. Based on an X- rays study and clinical examination, so far the owners were discouraged to pursue the further surgical treatment, because the procedure was supposed to be too aggressive and painful. The dog was prescribed palliative NSAIDs therapy.

 

 

Clinical examination

 

Fig1

Fig.1

We did a thorough clinical exam, revealing normal behaviour, good over-all body condition; signs of multiple joint arthritic diseases were found- elbows and stifles decreased ROM and capsules thickening. On the right cranio- ventral thoracic wall we found protruding, egg- size oval mass, widely and firmly connected to the rib cage (Fig.1).

 

 

 

Diagnostics

 

Radiograph of the right elbow revealed advanced elbow arthritic changes.

Fig 2

Fig.2

Additionally, orthogonal thoracic radiographs (+ oblique one) were done, demonstrating large infiltrating mass, with heterogenous lytic and proliferative mineralised pattern, originating at the costo-chondral junction of the 4-th rib (Fig.2).

 

 

 

 

 

unnamed

Fig.3

A fine needle aspiration was done and evaluated (Fig.3).

The pathologist remarks:

“Clusters of  fusiform mesenchymal cells, with obvious signs of malignancy- pleomorphism, increased anisokaryosis and anisocytsosis, basophilia, multinucleated cells . Occasional osteoclasts, macrophages and neutrophils were noted. No osteoid/chondroid was found in the examined material. The tumor was classified as malignant mesenchymal– fibrosarcoma, chondrosarcoma or osteosarcoma.”

 

 

Fig4

Fig.4

A computer tomographic study was accomplished and the mass’s margins investigated carefully. A mineralised tumor centre (from the distal third of the 4-th rib) was found; also soft tissue aggressive expansion in the neighbour intercostal spaces -3-th and 5-th. Typically for the chest wall masses, there was an eccentric growth- the 2/3 of the mass volume protruding into the throracic cavity, extruding the pulmonary parenchyma and contacting the heart on the right side. No lung metastases were noticed on the scans (Fig.4, video 1).

 

Complete blood work was done and found normal. Including normal Alkaline Phosphatase level, considered favorable prognostic factor.

 

After a discussion with the owner, a decision for surgical resection was made.

 

 

Anesthetic protocol

 

Premedication with Medetomidine and Butorphanol was used, followed by Propofol induction. The maintenance was sustained by Isoflurane and Ketamin drop in the fluid sack.

 

Peri-operative analgesia, Anesthetists remarks

 

fig 5

Fig.5

fig 6

Fig.6

The thoracic wall resection is considered very painful procedure, so a corresponding analgesic strategy was built and applied. A continuous post operative segmental epidural analgesia application was provided. T13—L1 epidural puncture (by Tuohy needle), was done and an epidural set catheter (B. Braun) was inserted till the 5-th thoracic vertebra(Fig.5-6). The catheter was safely attached and maintained for 48 h post op, during the patient’s stay in the clinic. The agent delivered through, was Levobupivacain (0,5 %), one 1ml every 4 hours, including pre op.

 

 

After the mass removal, a soaker catheter was sutured at the ribs resection edges; another one was applied between the skin and muscle flap, covering the defect. Both catheters were connected to an elastomeric pump (B. Braun), delivering locally 5 ml/h of 1% Lidocain for 96h (including outpatient period) post operatively.

 

The rationale behind additional soaker catheters was to suppress maximally the nociception transfer, including the sensation through the non- blocked cervical spinal nerves. Also we contemplated- removal of epidural catheter at the time of discharge, but leaving the delivery pump, providing residual local analgesia.

 

Cimicoxib (Cimalgex) was prescribed for 10 days post op. No opioids were used in the recovery period.

 

 

 

Surgical protocol (surgeon remarks)

 

Fig7

Fig.7

Fig 8

Fig 8

Fig 9

Fig 9

fig10

Fig10

After macroscopic mapping and drawing, a rectangular shaped, full thickness (skin, muscle, ribs and pleura) en bloc excision was done (Fig.7).  This included partial ostectomy of 3-th, 4-th and 5-th ribs. Caudal intercostal thoracotomy was performed first, permitting evaluation of the intrathoracic extent of the tumor. Special attention was applied at the proximal approach to ligate safely the three intercostal arteries and veins. No visceral lung pleural or pericardium adhesion were noticed. Careful electrocautery haemostasis was done at the muscles’ cut edges.  The removed mass was macroscopically evaluated for “clean” margins, and a reconstruction of the large defect was preceded (Fig.8). A double (folded) polypropylene mesh (SURGIPRO®TYCO) was sutured to the wound edges, using simple interrupted pattern (3-0 PDS material). A latissimus dorsi muscle flap was advanced to cover and “seal” the defect (Fig.9). The air content was evacuated with aspirator on the final closure; no chest drain was left in the thorax. Two soaker catheters were applied in the wound; the skin was closed by double pedicle advanced flap technique and simple interrupted pattern (Fig.10).

 

 

 

 

Post operative care and follow up

 

 

 

Fig 11

Fig. 11

The dog’s chest was loosely bandaged; the elastomeric pump and epidural catheter were securely fixed to the body(Fig.11). I.v. antibiotics and fluid support was continued for 24 hours post op.

Provided very effective local analgesia- the dog revealed excellent comfort immediately after the surgery (video 2,3,4). We paid special attention to any pain signs- excessive vocalization, hyper-excitement, panting, tachycardia, behavior abnormalities, etc. No such were present and the patient started eating the next day after surgery; it was discharged 48 after the procedure. No ambulation deficits were seen with the Levobupivacain application. The elastomeric pump was removed on the 4-th day. Mild to moderate serosanguineous discharges from the wound were present for 10 days after the surgery.

On the 14 days recheck the wound was healed and the sutures were removed; the patient showed excellent clinical recovery (Fig.12).

 

 

 

 

Discussion

 

 

The surgical excision is considered the first treatment of choice for malignant rib tumors, but a question about the long term prognosis and rationale behind an aggressive surgery could be raised. As mentioned above, the most common rib tumors are osteosarcomas (OS)  and chondrosarcomas(CS). They have quite different prognosis- OS is rarely cured, whereas CS could be cured with surgery alone. Dogs with osteosarcoma that have elevation of the Alkaline phosphatase level have a much lower median survival times 6. Chemotherapy significantly increases the survival of dogs with rib OS- from a few months to about 9.5 months. Roughly survival time is increased 4 times with chemotherapy + radical resection, compared to surgery alone. Chondrosarcomas have a very good chance to be cured with surgery alone with median survival times exceeding 3 years. The other common type -fibrosarcoma and hemangiosarcoma have intermediate metastatic potential between the other two. Survival times ranging from 120-450 days with chest wall resection alone 7.

 

Dealing with motivated owners, a patient in good general health, with normal AP, and need for moderately large rib case resection size, we found good indications for tumor removal without preliminary histological verification. We suggested acceptable life expectancy in the worst tumor type scenario (the option for chemotherapy was available). While respecting previous vets’ opinions, we took into consideration the stated in the literature fact that dogs tolerate removal of a large portion of the rib cage very well.

 

Despite all this encouraging decision making facts, we would have fought ethical issues in a scenario we weren’t able to provide sufficient peri-operative analgesia of the patient. Except the ethical side, the pain associated with thoracoectomies may have potentially lethal consequence for the patient cardiopulmonary status after surgery. A thoracoectomy requires a very painful excision, involving multiple muscle layers, rib resection, and continuous motion as the patient breathes. Sub-optimal management of pain has major respiratory consequences. Inspiration is limited by pain, which leads to reflex contraction of expiratory muscles, and consecutively to diaphragmatic dysfunction (decreased functional residual capacity and atelectasis, hypoxemia).Treatment of acute post-thoracotomy pain is particularly important not only to keep the patient comfortable but also to minimize pulmonary complications 8.

 

In the veterinary literature there are suggestion for various types of analgesia provided after thoracotomies-  intercostal blocks, intrapleural lidocaine, incisional pain soaker catheters9; systemic agents as NSAIDs, opioids, NMDA antagonists (ketamine),etc. There is plenty of space for objective evidence based studies, proving the best analgesic protocol, yet.

In the presented case we applied sophisticated but uncommon noxious stimulus blockage strategy. The thoracic epidural catheter insertion is technically demanding procedure but it is very powerful tool for both intra and post operative pain control 10. Even more, it allows even preemptive pain blockage. So-called preemptive analgesia is intended to prevent the establishment of central sensitization caused by surgery induced injuries. Evidence from basic research has indicated that analgesic drugs are more effective if administered before, rather than after, a noxious stimulus.  Human studies report that the area of post-thoracotomy pain is more discrete and largely restricted to the site of surgery. Hence, any benefit of preemptive epidural analgesia is, theoretically, more apparent in thoracic surgery than in abdominal surgery.

 

It is interesting if the present tumor or the arthritic elbow lesions caused the primary clinical sign- front right leg lameness. Lameness of the forelimb had been described with costal tumors, located within the first four ribs 11. Possible mechanism is pain translation to the nerves to the limb, mechanical interference with movement or invasion into the muscles of the forelimb. After the surgical excision the owners reported lameness disappearance, supporting the tumor as the real cause.

 

 

CONCLUSIONS

 

Excision of malignant chest wall masses could be very successful. It is feasible to achieve clean cut margins; large residual wall defects could be managed with combined reconstruction techniques. Never mind the aggressive character of the procedure, an excellent patient comfort should be achieved with a combination of thoracic epidural and local wound nerve nociception blockage, as in this case.

 

 

Comments:

 

Just before the submission of this case report the histopathology result was received. It concluded:

 

Mass, originating from spindeloid to pleomorphic cells, highly cellular. The cells were round, organized in bundles and solid formations. There was moderate to marked anisokaryosis and anisocytsosis; mitotic figures frequently present, multifocally there is osetoid production.

 

Diagnosis: Malignant pleomorphic neoplasia, suspicious for osteosarcoma.

 

Long term prognosis:

 

In the case, no local recurrence is expected because of the wide margins excision. Generally the median survival time (MST) for dogs with rib OSA is 90-120 days with surgery alone and 240-290 days with surgery and adjunctive chemotherapy, and death is caused by distant metastases.  Age, weight, sex, number of ribs resected, tumor volume, and total medication dose do not influence survival disease-free interval 12.

 

A chemotherapy protocol is already being contemplated:

Carboplatin 300mg/sq.m.; 4 treatments q 21 days (Withrow and MacEwen Small Animal Clinical Oncology,2007)

 

 

If available, the long term result and the survival time of the patient will be followed and shared through the journal.

Pacemaker implantation (PMI) as treatment for AVB III and very slow ventricular escape rhythm in a geriatric canine patient

2 д-р Ранко Георгиев

Dr Ranko Georgiev

Ranko Georgiev1, Hristina Shukerova2, Nadezhda Petrova3

1,2,3 DVM, Central Veterinary Clinic, Sofia, Bulgaria

Introduction:

Pacemaker implantation is the most effective treatment for ‘syncope and severe exercise intolerance’ – related arrhythmias; however when searching for the best clinical decision for some older dogs, the risk of anesthesia often outweighs the benefits. We would like to share a case where the old age was not a problem.

Case presentation:

Larry was a 17-year old MI mix breed dog admitted because of increasingly frequent exercise intolerance episodes during the past few months. Furthermore, the last week the patient was very week, unable to stand on his feet and with a depressed overall clinical status. On a clinical presentation with the referring vet а bradycardia was noted and the patient referred to us for a Cardiology consult.fig 1 Lari-Ro-LLR

During auscultation, a slow regular rhythm was detected with heart rate of 20 bpm classified as ventricular escape rhythm during the normal ECG. A 24hour Holter monitor revealed complete AV block (AVB III) throughout the study with an average rate of 31 bpm, occasional VE beats with some pairs, triplets and short runs; no pauses greater than 5 sec were noted. The slowest heart rate detected was 20 bpm.fig 3 echocardio

Complete blood count and biochemical profile were normal. Radiography and echocardiography revealed generalized cardiomegaly, with mild-to-moderate mitral and tricuspid regurgitation and decreased contractility. During the abdominal FAST study a small amount of free fluid was noted – defined as a transudate on diagnostic abdominocenthesis. Lari_20150811163929_1640560

A diagnosis of complete AV block with clinical signs of right sided congestive heart failure was made and pacemaker implantation was decided. A VVI, bipolar, passive lead was fluoroscopically placed, under anesthesia, through the right jugular vein into the right ventricle, where it was successfully lodged.Lari_20150814181226_1819550 The lead was connected to a generator, which was later fixed in the subcutaneous tissue dorsally to the cervical vertebrae. A temporary pacemaker was used when the dog developed asystole during the procedure. Recovery from the surgery was uneventful, with the pacemaker capturing normally. The pacing rate was set to 100 bpm. The system used was a ‘St Jude’ one.r1

Our anesthesia protocol with this patient was routine for the procedure of a PMI – premedication with Midazolam and Buprenorphine, induction with Etomidate, intubation and maintenance with Isoflurane. The post procedure treatment was only with Cefazolin iv for the next few days.fig 4 PMI-procedure-1fig 5 PMI-procedure-2

The use of a temporary lead and/or an external pacemaker is highly advisable in patients who are depended on their escape rhythm.

Comments:

Even though Larry recovered from the general anesthesia normally he was unable to stand on his feet for additional 5 days. He was bright, alert and responsive, with good appetite and normal consciousness, but with an impaired proprioception. We attributed this to the long period with severe bradycardia (HR of 20 bpm) and potential vasoconstriction/reperfusion complications. There is some data in the human medicine literature concerning PMI in old people with preexisting severe bradycardia, who reported pain in the extremities post the procedure.

Other factors such as chronic joint and spinal diseases could have been the cause of the slow recovery as well. The myoglobin levels were not checked prior to the PMI unfortunately.fig 6 flororfig 8 Lari-Ro-LLR-post-PMI

Conclusions:

Pacemaker implantation may be warranted even in older dogs with ‘syncope and severe exercise intolerance’ – related arrhythmias.r2

7 months post the procedure Larry is still doing great; in this period he underwent two additional major surgeries for a prostate abscess – with no anesthesia complications.581708_10201218994737586_1026692492_n