Diagnosis of pulmonary hypertension

Pulmonary hypertension may complicate a variety of congenital or acquired cardiac and pulmonary conditions. This vascular disorder results from conditions that lead to a chronic increase in left atrial pressure, increased pulmonary blood flow, or increased pulmonary vascular resistance. Definitive diagnosis requires cardiac catheterization and detection of systolic and mean pulmonary artery pressures exceeding 30 and 20 mm Hg, respectively. Clinical signs and historical complaints reflect underlying cardiac or pulmonary conditions, although syncope may be a predominant finding. Radiographic changes are nonspecific; however, right ventricular enlargement and enlarged pulmonary arteries should increase suspicion for the disorder. Estimates of pulmonary arterial pressure may be obtained through Doppler echocardiography. This requires detection of a high-velocity regurgitant jet across the tricuspid or pulmonic valve. Further investigation is required to determine how pulmonary hypertension impacts therapy and prognosis for dogs and cats with cardiac and pulmonary diseases.     

Closed Transventricular Dilation of Discrete Subvalvular Aortic Stenosis in Dogs

Discrete subvalvular aortic stenosis with peak systolic pressure gradients of more than 60 mm Hg was treated by closed transventricular dilation in six young dogs. Peak systolic pressure gradients were measured by direct catheterization before surgery, immediately after dilation, and 3 months after surgery. Maximum instantaneous pressure gradients were measured by continuous wave Doppler echocardiography before surgery and 6 weeks to 9 months after surgery. All dogs survived the procedure, and two dogs were clinically normal after 9 and 14 months. Two dogs died at week 6 and month 7. One dog was receiving medication for pulmonary edema 15 months after surgery. One dog underwent open resection of the subvalvular ring at month 3, and was clinically normal 6 months after the second procedure. Complications included intraoperative ventricular fibrillation in one dog, and mild postoperative aortic insufficiency in one dog. Closed transventricular dilation resulted in an immediate 83% decrease in the peak systolic pressure gradient from a preoperative mean of 97 +/- 22 mm Hg to a mean of 14 +/- 15 mm Hg. However, systolic pressure gradients measured by direct catheterization at month 3 (77 +/- 26 mm Hg), and by Doppler echocardiography at week 6 to month 9 (85 +/- 32 mm Hg) were not significantly different from preoperative values, which suggested recurrence of the aortic stenosis. Closed transventricular dilation should not be considered a definitive treatment for discrete subvalvular aortic stenosis in dogs, but may be useful in young dogs with critical aortic stenosis as a bridge to more definitive surgery.     

Echocardiographic estimation of mean left atrial pressure in a canine model of acute mitral valve insufficiency

High mean left atrial pressure (MLAP) due to canine degenerative mitral valve disease is associated with clinically relevant morbidity and mortality. The ability to noninvasively measure MLAP would assist in the diagnosis and treatment of disease. Doppler echocardiography allows measurement of early transmitral blood flow (E) and the velocity of the mitral valve annulus (Ea). The ratio of early mitral inflow velocity to early mitral annular velocity (E: Ea) correlates well with MLAP in human subjects. We sought to determine the ability of E: Ea to predict MLAP in dogs with experimentally induced mitral regurgitation. Nine anesthetized purpose-bred dogs underwent placement of a Swan-Ganz catheter into the left atrium and recording of MLAP. Simultaneous transthoracic echocardiographic and hemodynamic studies were performed after acute chordae tendineae rupture and during IV infusion with nitroprusside (2.5-5.0 microg x kg(-1) x min(-1)) or hydralazine (1-1.5 mg/kg). Mitral regurgitant fraction, measured by single-plane angiography and thermodilution, ranged from 17% to 81%. MLAP increased from 5.4 +/- 2.5 mm Hg to 17.4 +/- 9.4 mm Hg after creation of mitral valve regurgitation (MR; P = .018). Forty sets of echocardiographic measurements were obtained from 7 dogs, and E, as well as E: Ea, were linearly related to MLAP. The R2 value for the linear regression equation containing E: Ea as the dependent variable (0.83) was greater than that for E (0.73). The 95% confidence intervals were calculated for predicting MLAP = 20 mm Hg from E:Ea, and E:Ea >9.1 or <6.0 indicated a 95% probability that MLAP was >20 mm Hg or <20 mm Hg, respectively. Echocardiography can be used to predict MLAP in isoflurane-anesthetized dogs with experimentally induced acute mitral valve insufficiency.     

Cardiac effects of pulmonary disease.

Pulmonary hypertension (PHT) is the primary cardiac consequence of pulmonary disease. It develops as alveolar hypoxia of pulmonary disease, coupled with vasoactive and mitogenic substances released from pulmonary endothelial and vascular smooth muscle cells damaged by the primary disease process, mediates arterial vasoconstriction and vascular remodeling to raise pulmonary vascular resistance. Independent of the underlying pulmonary disease, PHT produces clinical signs of respiratory distress, exercise intolerance, syncope, and right heart failure. Diagnosis of PHT is made by estimation of pulmonary artery pressures by means of continuous-wave Doppler echocardiographic assessment of tricuspid or pulmonic regurgitant flow velocity. Treatment of PHT is directed at the underlying pulmonary disease but may also aim to attenuate pulmonary artery pressure and limit the clinical sequelae of PHT. No treatments are of proven benefit in veterinary patients; irrespective of the nature of the inciting pulmonary disease, the prognosis is often grave.     

Doppler echocardiography-derived evidence of pulmonary arterial hypertension in dogs with degenerative mitral valve disease: 86 cases (2001-2005)

OBJECTIVE: To determine the prevalence of Doppler echocardiography-derived evidence of pulmonary arterial hypertension (DEE-PAH) in dogs with mitral valve disease (MVD) classified according to the International Small Animal Cardiac Health Council (ISACHC) heart failure classification scheme and various echocardiographic and Doppler indices of MVD severity. DESIGN: Retrospective case series. ANIMALS: 617 dogs examined from 2001 to 2005 with MVD in ISACHC classes I to III. PROCEDURES: Dogs were examined echocardiographically. Criteria used for systolic and diastolic DEE-PAH were detection of high tricuspid (> or = 2.5 m/s) and telediastolic pulmonic (> or = 2.0 m/s) valvular peak regurgitant jet velocities, respectively, by use of continuous-wave Doppler echocardiography. RESULTS: 86 (13.9%) dogs with MVD had a diagnosis of DEE-PAH. Severity and prevalence of DEE-PAH increased with ISACHC class (3.0%, 16.9%, 26.7%, and 72.2% prevalences for ISACHC classes Ia, Ib, II, and III, respectively). A significant correlation between systolic or diastolic pulmonary arterial pressure and left atrial-to-aortic diameter ratio (LA/Ao) was detected. Doppler echocardiography-derived evidence of pulmonary arterial hypertension was detected in 18 dogs with values of LA/Ao within reference range, all of which had moderate (n = 2 dogs) or severe (16) mitral valve regurgitation on color Doppler imaging. CONCLUSIONS AND CLINICAL RELEVANCE: The prevalence and degree of DEE-PAH were related to the severity of MVD. Changes associated with DEEPAH may be detected in early stages of the disease, but only in dogs with severe mitral valve regurgitation.     

Sildenafil citrate therapy in 22 dogs with pulmonary hypertension

BACKGROUND: Pulmonary hypertension (PH) is a disease condition characterized by abnormally increased pulmonary artery pressures and often is associated with a poor prognosis. Sildenafil is a phosphodiesterase inhibitor that causes pulmonary arterial vasodilation and reduction in pulmonary artery pressures. HYPOTHESIS: Treatment with sildenafil will improve echocardiographic determinants of PH in dogs, while also improving quality of life and survival. ANIMALS: Twenty-two dogs with clinical and echocardiographic evidence of pulmonary hypertension. METHODS: A retrospective study evaluating the effects of sildenafil on physical examination, ECG and radiographic findings, blood pressure and echocardiographic findings of PH, clinical score, and outcome was completed. PH was defined as a peak tricuspid regurgitation flow velocity > or = 2.8 m/s or a peak pulmonic insufficiency flow velocity > or = 2.2 m/s. RESULTS: Sixteen of 22 dogs with PH were elderly females of small body size. Their clinical score was significantly improved (P = .0003) with sildenafil treatment, but physical examination findings remained unchanged. Heart rate, respiratory rate, vertebral heart size, ECG heart rate, and systolic blood pressure did not change significantly with sildenafil treatment (P > .05). Peak tricuspid regurgitation flow velocities did not change significantly with the treatment of sildenafil, but selected systolic time intervals were significantly improved. Survival times for all dogs ranged from 8 to > 734 days. CONCLUSIONS AND CLINICAL IMPORTANCE: Sildenafil did not significantly lower the degree of measurable PH in dogs. Clinical improvement and increased quality of life was seen with sildenafil treatment, despite lack of significant change in other variables.     

Pulmonary artery dissection following pulmonary balloon valvuloplasty in dogs

Introduction/objectivesPulmonary artery dissection is a rare complication following balloon valvuloplasty for pulmonic stenosis. We sought to report the rate of this complication in dogs and describe the demographic, clinical, procedural, and outcome data in affected dogs.Animals, materials and methodsMedical records at a single academic institution between 2002 and 2021 were reviewed for dogs with pulmonic stenosis treated by a balloon valvuloplasty. Dogs were included for evaluation if there was evidence of pulmonary artery dissection on echocardiography or necropsy following balloon valvuloplasty. The demographic, clinical, surgical, and follow-up information were then recorded.ResultsSix dogs were included from 210 balloon valvuloplasty procedures for pulmonic stenosis giving a 3.9% rate of pulmonary dissection. There was a variety of signalment, pulmonary valve morphologies, and balloon catheter types used in each dog. All dogs had severe pulmonic stenosis (median pressure gradient of 208 mmHg, range 94–220 mmHg) with 5/6 dogs having a pressure gradient >144 mmHg. The median balloon to pulmonary valve annulus ratio was 1.35 (range 1.25–1.5). Three dogs died perioperatively, and three dogs were alive at follow up 3.3, 4.0, and 4.1 years postoperatively.ConclusionPulmonary artery dissection is a rare complication following balloon valvuloplasty for pulmonic stenosis. Extreme elevations in preoperative pulmonary valve flow velocity were common. Prognosis is variable, with a potential 50% perioperative survival rate, but extended survival times were noted in those patients discharged from hospital.     

Doppler echocardiographic evidence of pulmonary hypertension in dogs: a retrospective clinical investigation

Pulmonary hypertension (PH) decreases resistance to fatigue and life expectancy. The aim of this study was to correlate some indirect Doppler indices of PH with tricuspid and pulmonary regurgitation criteria and to relate PH on different indices with the severity of clinical signs. Furthermore the pathogenetic mechanisms associated to PH development were discussed. Dogs with Doppler echocardiographic evidence of PH diagnosed by assessment of pulmonary and tricuspid regurgitant jet velocity were selected, their clinical records were reviewed and a clinical score was computed. Seventeen cases of PH were identified. The degree of PH was assessed based on systolic or diastolic pulmonary pressure and the indirect Doppler indices (AT/ET and Tei Index) were calculated; data were statistically evaluated. Indirect Doppler indices were calculated also in a control group of seven healthy dogs. The most common clinical signs were coughing, dyspnea and syncope; the most common condition associated to PH development was the left-sided valvular heart disease. A significant positive correlation was found between Tei Index and both the systolic pressure and the severity of PH while no correlations were found between PH on different indices and clinical score and/or severity of clinical signs. Results of this study suggest that Tei-index could be an useful support not only to reveal PH but also to give information on the severity of PH. The clinical picture in dogs with PH is apparently unpredictable and not strictly correlated with the severity of PH.     

Outcome in 55 dogs with pulmonic stenosis that did not undergo balloon valvuloplasty or surgery

Objective : To determine the outcome, independent predictors of cardiac death, and the Doppler‐derived pressure gradient cut‐off for predicting cardiac death in dogs with pulmonic stenosis, with or without tricuspid regurgitation, that do not undergo balloon valvuloplasty or valve surgery. Methods : Review of medical records of two UK referral centres between July 1997 and October 2008 for all cases of pulmonic stenosis that had no balloon valvuloplasty or valve surgery. Inclusion criteria included a diagnosis of pulmonic stenosis; spectral Doppler pulmonic velocity greater than 1·6 m/s; characteristic valve leaflet morphological abnormalities. Exclusion criteria included concurrent significant cardiac defects, including tricuspid dysplasia. Dogs with tricuspid regurgitation were included. Dogs were classified according to Doppler‐derived pressure gradients into mild, moderate or severe pulmonic stenosis categories. Results : Presence of tricuspid regurgitation and severe stenosis were independent predictors of cardiac death. A pulmonic pressure gradient of more than 60 mmHg was associated with 86% sensitivity, and 71% specificity of predicting cardiac death. Clinical Significance : There is an increased probability of cardiac death in those cases which have a pulmonary pressure gradient greater than 60 mmHg and tricuspid regurgitation, though the effect of severity of tricuspid regurgitation on outcome was not measurable because of small sample sizes. These animals might benefit from intervention.     

Surgical treatment of severe pulmonic stenosis under cardiopulmonary bypass in small dogs

Objectives : The aim of this study was to report the long‐term outcome of the surgical palliation of pulmonic stenosis in dogs. Methods : The subjects comprised three female and six male dogs, mean (±sd) age: 23 (±25) months, mean (±sd) weight: 3·4 (±2·1) kg, diagnosed with severe pulmonic stenosis and right ventricular hypertrophy, with an average preoperative pressure gradient of 153 (±43) mmHg on echocardiography. Results : The pressure overload with severe pulmonic stenosis was reduced by valvotomy, i.e., open pulmonary valve commissurotomy, with/without biomembrane patch grafting, under cardiopulmonary bypass. The postoperative pressure gradient at 1 to 7 days was significantly decreased to 65 (±39) mmHg (P<0·05). The reduced pressure gradient was maintained at 58 (±38) mmHg at final follow‐up. Clinical Significance : Open valvotomy, pulmonary valve commissurotomy and biomembrane patch grafting were effective in reducing obstruction in severe pulmonic stenosis in dogs.     

Doppler-derived velocity of blood flow across the cardiac valves in the normal dog.

Doppler echocardiography is a relatively new procedure used to assess certain cardiovascular disorders in the dog. The objectives of this study were to determine the range of values for the maximal peak velocity of blood flow across each of the four cardiac valves in a sample population of normal adult dogs, using duplex continuous wave Doppler echocardiography, and to determine the optimal tomographic planes to use for an adequate continuous wave Doppler evaluation of the canine heart. Twenty normal dogs were examined to obtain values for peak transvalvular velocity for each of the four cardiac valves. The mean values +/- 1 SD, in cm/s were: 98.1 +/- 9.4 for the pulmonary valve imaged from the left side of the chest, 95.5 +/- 10.3 for the pulmonary valve imaged from the right side of the chest (n = 19), 118.1 +/- 10.8 for the aortic valve, 86.2 +/- 9.5 for the mitral valve and 68.9 +/- 8.4 for the tricuspid valve. Regurgitation was detected across the pulmonic valve in 14 of the 20 dogs, and across the tricuspid valve in ten dogs. The analysis of the tomographic images confirmed that for a complete assessment of a given intracardiac valve, the valve must be examined from all possible directions to obtain maximum values for peak velocity.     

Pulmonary arteriopathy and idiopathic pulmonary arterial hypertension in six dogs

Pulmonary arteriopathy (PA) is the pathologic hallmark in human medicine of diffuse constrictive (medial and intimal remodeling) or multifocal complex (plexiform and dilatative lesions) arterial lesions, or both, that lead to irreversible obliteration of the arterial lumen. Clinically, PA leads to pulmonary arterial hypertension (PAH), of which idiopathic (IPAH) is one of the 5 subsets, and ultimately, to right-sided heart failure (RHF). Clinical and pathologic findings from 6 dogs with diagnosis of IPAH and PA were reviewed. These dogs were of various pure (5/6, 83%) and mixed (1/6, 17%) breeding, 5 months to 9 years (mean 5.2 years) old, and predominantly female (4/6, 67%) and reproductively intact (4/6, 67%). Doppler echocardiography (n = 5) indicated increased pulmonary arterial pressures during systole (70-135 mm Hg, mean 98 mm Hg) and diastole (35-80 mm Hg, mean 58 mm Hg). All 6 dogs had right ventricular pressure overload, right ventricular eccentric hypertrophy, and RHF. Histologic examination confirmed the clinical diagnosis of IPAH in all dogs, revealing PA characterized by 1 of the 4 main human histologic subsets: 1) isolated medial hypertrophy (1/6, 17%); 2) medial hypertrophy-intimal thickening without the plexiform lesion (1/6, 17%); 3) medial hypertrophy-intimal thickening concurrent with the plexiform lesion, which often was regionally clustered and situated near branching points of the respiratory artery, the poststenotic dilatation lesion, and vasculitis (4/6, 66%); and 4) isolated arteritis (1/6, 17%). Ancillary lesions similar to those in humans also complicated the PA (5/6, 83%). The complex lesions and ancillary exudative alveolitis seemed to be important indicators of severe, likely rapidly progressive and fatal, IPAH.     

Pulmonic stenosis in the dog: 29 cases (1975-1984)

In a retrospective study of 29 dogs with congenital pulmonic stenosis, we evaluated the clinical, radiographic, angiocardiographic, and cardiac catheterization data. Eighteen dogs had no clinical signs of disease and were referred for evaluation of a previously detected cardiac murmur, 5 dogs had congestive right-sided heart failure, and 5 dogs were examined for exercise intolerance or syncope. Dogs with heart failure tended to be older than dogs without clinical signs of heart failure (19.3 months vs 12 months). All dogs had radiographic or electrocardiographic evidence of right ventricular enlargement. Poststenotic dilatation of the main pulmonary artery and apparent pulmonary undercirculation were observed frequently on survey radiographs. Isolated pulmonic valve dysplasia, representing a range of angiographic pulmonic valve abnormalities, was evident in 88% of the available 26 angiographic studies, whereas subvalvular stenosis was uncommon and observed in only 2 dogs. Muscular hypertrophy of the right ventricular infundibulum and supraventricular crest were observed in 96% and 25% of the angiocardiograms, respectively. Poststenotic dilatation of the main pulmonary artery was observed in every dog. A ratio between the width of the main pulmonary artery and the valve annulus was useful in identifying pulmonic stenosis and distinguishing this anomaly from other congenital malformations. The degree of poststenotic dilatation did not appear to be related to the severity of the systolic pressure gradient, which ranged from 20 to 228 mm of Hg (mean, 93 mm of Hg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Balloon valvuloplasty in 30 dogs with pulmonic stenosis: effect of valve morphology and annular size on initial and 1-year outcome

Case records of 30 dogs in which valvular pulmonic stenosis (PS) was treated by balloon dilation were reviewed retrospectively. Physical examination, thoracic radiographs, 9-lead ECG, echocardiography, and Doppler studies were performed in all dogs. Two-dimensional and Doppler echocardiography were repeated after 24 h and 1 year after treatment. Dogs were divided into 2 groups based on their valvular anatomy on echocardiography and aortic:pulmonary ratio: 18 had type A PS with normal annulus diameter and aortic:pulmonary ratio < or = 1.2, and 12 had type B PS with pulmonary annulus hypoplasia and aortic:pulmonary ratio > 1.2. Most dogs in the type B group were brachycephalic and had no poststenotic dilatation on thoracic radiographs. Of the dogs with type A stenosis, 100% survived valvuloplasty with resolution of clinical signs. At 1-year follow-up, 94.4% were still alive and remained asymptomatic. Of those with type B stenosis, 66.6% had favorable outcome postvalvuloplasty. At 1-year follow-up, 66.6% of dogs were alive, and resolution of clinical signs was obtained in 50%. This study revealed the immediate and long-term efficacy of balloon valvuloplasty in dogs with PS.     

An Open Patch-Graft Technique for Correction of Pulmonic Stenosis in the Dog

An open patch-graft technique for correction of pulmonic stenosis was performed in four dogs. A synthetic patch-graft was presutured to a partial-thickness incision in the right ventricular outflow tract and to the pulmonary artery along its cranial border. The pulmonary artery and right ventricle were incised during venous inflow occlusion, and dysplastic pulmonic valve leaflets were excised. The arteriotomy was closed by suturing the caudal margin of the incision to the patch-graft. The entire procedure was performed during mild hypothermia (30 degrees - 32 degrees C). The mean circulatory arrest time was 5.5 +/- 0.2 minutes. The mean systolic pressure gradient across the pulmonic valve before surgery was 121 +/- 29 mm Hg; after surgery it was 9 +/- 2 mm Hg.     

Examination of quantitative analysis and measurement of the regurgitation rate in mitral valve regurgitation by the "proximal isovelocity surface area" method

In 33 dogs with mitral valve insufficiency (MR), assessed as severe by semi-quantitative color flow Doppler echocardiography, regurgitation volumes were measured by the "Proximal Isovelocity Surface Area" (PISA) method. Good correlation (p<0.01, r=0.97) between the regurgitation volumes determined by the "PISA" and pulsed Doppler methods was confirmed. As evaluated by the "PISA" method, regurgitation rates in the 32 dogs with measurable regurgitation volumes ranged from 23 to 73%, with a mean of 51.6 +/- 11.8%. Regurgitation volumes ranged from 3.3 to 32 ml, with a mean of 8.4 +/- 6.4 ml.     

Associations between thoracic radiographic changes and severity of pulmonary arterial hypertension diagnosed in 60 dogs via Doppler echocardiography: A retrospective study

Doppler echocardiography is a noninvasive method for estimating and grading pulmonary arterial hypertension. No current literature associates significance of radiographic findings with severity of pulmonary arterial hypertension. We hypothesized that the number and conspicuity of radiographic findings suggestive of pulmonary arterial hypertension would be greater based on the severity of pulmonary arterial hypertension. Dogs with pulmonary arterial hypertension and normal control dogs were included in this retrospective, case control study. Three radiologists blinded to echocardiographic results scored thoracic radiographs for right ventricular and main pulmonary artery enlargement and pulmonary lobar artery enlargement, tortuosity, and blunting by multiple methods. Presence or absence of each finding was scored in an additive fashion and averaged for each grade of pulmonary arterial hypertension severity. Seventy‐one dogs (60 dogs with pulmonary arterial hypertension and 11 control dogs) of which some had multiple studies were included: 20 mild, 21 moderate, 25 severe, and 11 absent pulmonary arterial hypertension. The following radiographic findings were significantly associated with increasing pulmonary arterial hypertension severity: right ventricular enlargement by “reverse D” and “3/5–2/5 cardiac ratio” methods, main pulmonary artery enlargement, and caudal lobar artery enlargement by the “3rd rib” method. Mean scores for severe pulmonary arterial hypertension and normal dogs were significantly different (P‐value < 0.0001). Mean scores between different pulmonary arterial hypertension grades increased with severity but were not statistically significant. Individually and in combination, radiographic findings performed poorly in differentiating severity of pulmonary arterial hypertension. Findings indicated that thoracic radiographs should be utilized in conjunction with Doppler echocardiography in a complete diagnostic work‐up for dogs with suspected pulmonary arterial hypertension.     

Double-Outlet Right Ventricle for Relief of Pulmonic Stenosis in Dogs An Experimental Study

Relief of right ventricular outflow obstruction with a valveless Dacron conduit from the right ventricle to pulmonary artery was accomplished in 12 normal dogs. The procedure involved the development of a surgical technique without cardiopulmonary bypass, hypothermia, and/or venous occlusion; the development of a ventricular coring instrument; the fabrication of a wire supported Dacron conduit; the development of a basketed insert cannula; and the creation of an experimental model of pulmonic stenosis. Of the 12 dogs operated, two died intraoperatively, three died postoperatively, and seven were electively euthanized postoperatively. Relief of the right ventricular outflow obstruction was documented in all cases by a reduction in mean peak right ventricular pressure, improvement of mean arterial pressure, decrease in mean right atrial pressure, and an increase in mean pulmonary artery pressure. The pulmonary insufficiency created was considered a tolerable although not benign condition. The technique would be of particular value in dogs with severe right ventricular hypertrophy.     

Pre- and post-operative cardiac evaluation of dogs undergoing lobectomy and pneumonectomy

This study aimed to assess the influence of lobectomy and pneumonectomy on cardiac rhythm and on the dimensions and function of the right-side of the heart. Twelve dogs undergoing lobectomy and eight dogs undergoing pneumonectomy were evaluated preoperatively and one month postoperatively with electrocardiography and Doppler echocardiography at rest. Pulmonary artery systolic pressure (PASP) was estimated by the tricuspid regurgitation jet (TRJ) via the pulse wave Doppler velocity method. Systemic inflammatory response syndrome criteria (SIRS) were also evaluated based on the clinical and hematological findings in response to lobectomy and pneumonectomy. Following lobectomy and pneumonectomy, we predominantly detected atrial fibrillation and varying degrees of atrioventricular block (AVB). Dogs that died within seven days of the lobectomy (n = 2) or pneumonectomy (n = 1) had complete AVB. Preoperative right atrial, right ventricular, and pulmonary artery dimensions increased gradually during the 30 days (p<0.05) following pneumonectomy, but did not undergo significant changes during that same period after lobectomy. Mean PASP was 56.0 ± 4.5 mmHg in dogs having significant TRJ after pneumonectomy. Pneumonectomy, but not lobectomy, could lead to increases (p<0.01) in the SIRS score within the first day post-surgery. In brief, it is important to conduct pre- and postoperative cardiac evaluation of dogs undergoing lung resections because cardiac problems are a common postoperative complication after such surgeries. In particular, complete AVB should be considered a life-threatening complication after pneumonectomy and lobectomy. In addition, pneumonectomy appears to increase the likelihood of pulmonary hypertension development in dogs.